EX(w/o STI)-9
Front Exhaust Pipe
EXHAUST
2. Front Exhaust Pipe
A: REMOVAL
CAUTION:
Vehicle components are extremely hot after driving. Be wary of receiving burns from heated parts.
1) Remove the collector cover.
(1) Remove the clips (A).
(2) Hold the shaded area (B) by hand and carefully pull the RH side (C) upward.
(3) Hold the shaded area (D) by hand and carefully pull the LH side (E) upward.
2) Disconnect the ground terminal from battery sensor. <Ref. to NT-5, BATTERY, NOTE, Note.>
3) Remove the air intake duct. <Ref. to IN(w/o STI)-22, REMOVAL, Air Intake Duct.>
4) Remove the radiator sub fan and fan motor assembly. <Ref. to CO(w/o STI)-49, REMOVAL, Radiator Sub
Fan and Fan Motor.>
5) Lift up the vehicle.
6) Remove the under cover. <Ref. to EI-21, REMOVAL, Front Under Cover.>
7) Drain engine coolant. <Ref. to CO(w/o STI)-13, DRAINING OF ENGINE COOLANT, REPLACEMENT,
Engine Coolant.>
8) Lower the vehicle.
EX-03204
(A)
(B)
(C)
(E)
(D)
15WRX_STI_US_EN.book 9 ペー 01  
EX(w/o STI)-10
Front Exhaust Pipe
EXHAUST
9) Remove the bolts which secure the water pump pulley cover to the turbocharger stay.
10) Disconnect the engine coolant hose from the water pipe assembly.
EX-03039
EX-03125
15WRX_STI_US_EN.book 10 ペー   
EX(w/o STI)-11
Front Exhaust Pipe
EXHAUST
11) Remove the bolts which secure the intake duct No. 2 to the turbocharger.
12) Lift up the vehicle.
13) Disconnect the connector on the front oxygen (A/F) sensor from the engine harness, and remove the clip
(A) which secures the front oxygen (A/F) sensor harness to the water pump pulley cover.
EX-02979
(A)
EX-03028
15WRX_STI_US_EN.book 11 ペー   
EX(w/o STI)-12
Front Exhaust Pipe
EXHAUST
14) Disconnect the connector on the rear oxygen sensor from the engine harness, and disconnect the
ground cable from the exhaust pipe cover.
15) Disconnect the vacuum control hose from the wastegate control solenoid valve.
EX-03126
EX-03057
15WRX_STI_US_EN.book 12 ペー   
EX(w/o STI)-13
Front Exhaust Pipe
EXHAUST
16) Remove the bolts which secure the intake duct No. 1 to the turbocharger.
17) Remove the nuts which secure the center exhaust pipe (rear) to the center exhaust pipe (front).
EX-02984
EX-03127
15WRX_STI_US_EN.book 13 ペー   
EX(w/o STI)-14
Front Exhaust Pipe
EXHAUST
18) Remove the bolts, springs, and nuts which secure the rear exhaust pipe to the center exhaust pipe (rear).
EX-02971
15WRX_STI_US_EN.book 14 ペー   
EX(w/o STI)-15
Front Exhaust Pipe
EXHAUST
19) Remove the bolt which holds center exhaust pipe (rear) to the hanger bracket, and remove the center ex-
haust pipe (rear).
NOTE:
For CVT model, removing the exhaust pipe bracket from the center exhaust pipe (rear) will adversely affect
the positioning accuracy. Therefore, do not remove the bolts in section (a) shown in the figure.
CVT model
•MT model
EX-03148
(a)
EX-03138
15WRX_STI_US_EN.book 15 ペー   
EX(w/o STI)-16
Front Exhaust Pipe
EXHAUST
20) Disconnect the union screw pipe assembly from the oil pipe assembly, and disconnect the engine coolant
hose (A) from the water pipe RH.
CAUTION:
In order to prevent damaging the oil pipe assembly, fix the section (a) shown in the figure when loos-
ing the flare nut on the union screw pipe assembly, and avoid the part from rotating together while
loosening the nut.
21) Disconnect the turbocharger hose (B) from the oil pipe, and drain the engine oil in the oil catch tank.
NOTE:
Prepare the container for draining of engine oil.
22) Remove the bolts securing the oil catch tank to the turbo charger and the exhaust stay, and place the oil
catch tank aside so that it does not interfere operation.
EX-03043
(a)
(A)
(B)
IN-03379
15WRX_STI_US_EN.book 16 ペー   
EX(w/o STI)-17
Front Exhaust Pipe
EXHAUST
23) Remove the bolts which secure the turbocharger stay.
24) While holding the front exhaust pipe with transmission jack, remove the nuts which hold the front exhaust
pipe to the cylinder head exhaust port, and remove the front exhaust pipe.
EX-02987
EX-02988
15WRX_STI_US_EN.book 17 ペー   
EX(w/o STI)-18
Front Exhaust Pipe
EXHAUST
25) Remove the water pump pulley cover and exhaust pipe stay from the engine and turbocharger stay.
26) Remove the turbocharger stay from the engine.
EX-03030
EX-02990
15WRX_STI_US_EN.book 18 ペー   
EX(w/o STI)-19
Front Exhaust Pipe
EXHAUST
B: INSTALLATION
1) Install the turbocharger stay to the engine.
Tightening torque:
30 N·m (3.1 kgf-m, 22.1 ft-lb)
2) Install the water pump pulley cover and exhaust pipe stay to the engine and turbocharger stay.
Tightening torque:
19 N·m (1.9 kgf-m, 14.0 ft-lb)
EX-02990
EX-03030
15WRX_STI_US_EN.book 19 ペー   
EX(w/o STI)-20
Front Exhaust Pipe
EXHAUST
3) While holding the front exhaust pipe with transmission jack, set the front exhaust pipe, and install the nuts
which hold the front exhaust pipe to the cylinder head exhaust port.
NOTE:
Use a new gasket.
Tightening torque:
42.5 N·m (4.3 kgf-m, 31.3 ft-lb)
4) Attach the bolt which holds the turbocharger stay.
Tightening torque:
33 N·m (3.4 kgf-m, 24.3 ft-lb)
EX-02988
EX-02987
15WRX_STI_US_EN.book 20 ペー   
EX(w/o STI)-21
Front Exhaust Pipe
EXHAUST
5) Install the oil catch tank to the turbocharger and exhaust stay.
(1) Set the oil catch tank to the turbocharger, and temporarily tighten the bolts which secure the oil catch
tank to the turbocharger and exhaust stay.
NOTE:
Use a new gasket.
(2) Tighten the bolts which secure the oil catch tank to the turbocharger and exhaust stay in numerical or-
der as shown in the figure.
Tightening torque:
T1: 6.4 N·m (0.7 kgf-m, 4.7 ft-lb)
T2: 10.5 N·m (1.1 kgf-m, 7.7 ft-lb)
6) Connect the turbocharger hose (B) to the oil pipe.
IN-03379
(3)
(1)
(2)
T1
T2
IN-03380
15WRX_STI_US_EN.book 21 ペー   
EX(w/o STI)-22
Front Exhaust Pipe
EXHAUST
7) Connect the union screw pipe assembly to the oil pipe assembly, and connect the engine coolant hose (A)
to the water pipe RH.
CAUTION:
In order to prevent damaging the oil pipe assembly, fix the section (a) shown in the figure when tight-
ening the flare nut on the union screw pipe assembly, and avoid the part from rotating together while
tightening the nut.
Tightening torque:
20 N·m (2.0 kgf-m, 14.8 ft-lb)
8) Set the center exhaust pipe (rear), and temporarily tighten the bolt which holds the center exhaust pipe
(rear) to the hanger bracket.
CVT model
EX-03043
(a)
(A)
(B)
EX-02917
15WRX_STI_US_EN.book 22 ペー   
EX(w/o STI)-23
Front Exhaust Pipe
EXHAUST
•MT model
9) Install the bolts, springs, and nuts which secure the rear exhaust pipe to the center exhaust pipe (rear).
NOTE:
Use a new gasket.
Tightening torque:
18 N·m (1.8 kgf-m, 13.3 ft-lb)
EX-03138
EX-02971
15WRX_STI_US_EN.book 23 ペー   
EX(w/o STI)-24
Front Exhaust Pipe
EXHAUST
10) Install the nuts which secure the center exhaust pipe (rear) to the center exhaust pipe (front).
NOTE:
Use a new gasket.
Tightening torque:
42.5 N·m (4.3 kgf-m, 31.3 ft-lb)
11) Tighten the bolts which hold center exhaust pipe (rear) to the hanger bracket.
Tightening torque:
35 N·m (3.6 kgf-m, 25.8 ft-lb)
CVT model
EX-03127
EX-02921
15WRX_STI_US_EN.book 24 ペー   
EX(w/o STI)-25
Front Exhaust Pipe
EXHAUST
•MT model
12) Install the bolt which secures the intake duct No. 1 to the turbocharger.
NOTE:
Use new O-rings.
Be careful not to pinch the O-ring.
Tightening torque:
6.4 N·m (0.7 kgf-m, 4.7 ft-lb)
EX-03139
EX-02984
15WRX_STI_US_EN.book 25 ペー   
EX(w/o STI)-26
Front Exhaust Pipe
EXHAUST
13) Connect the vacuum control hose to the wastegate control solenoid valve.
14) Connect the connector on the rear oxygen sensor to the engine harness, and connect the ground cable
to the exhaust pipe cover.
Tightening torque:
7 N·m (0.7 kgf-m, 5.2 ft-lb)
EX-03057
EX-03126
15WRX_STI_US_EN.book 26 ペー   
EX(w/o STI)-27
Front Exhaust Pipe
EXHAUST
15) Secure the front oxygen (A/F) sensor harness to the water pump pulley cover with the clip (A), and con-
nect the front oxygen (A/F) sensor connector to the engine harness.
16) Install the under cover. <Ref. to EI-22, INSTALLATION, Front Under Cover.>
17) Lower the vehicle.
18) Install the bolts which secure the intake duct No. 2 to the turbocharger.
Tightening torque:
16 N·m (1.6 kgf-m, 11.8 ft-lb)
(A)
EX-03028
EX-02979
15WRX_STI_US_EN.book 27 ペー   
EX(w/o STI)-28
Front Exhaust Pipe
EXHAUST
19) Connect the engine coolant hoses to the water pipe assembly.
20) Attach the bolt which secures the water pump pulley cover to the turbocharger stay.
Tightening torque:
33 N·m (3.4 kgf-m, 24.3 ft-lb)
21) Install the radiator sub fan and fan motor assembly. <Ref. to CO(w/o STI)-49, INSTALLATION, Radiator
Sub Fan and Fan Motor.>
22) Install the air intake duct. <Ref. to IN(w/o STI)-22, INSTALLATION, Air Intake Duct.>
23) Connect the ground terminal to battery sensor. <Ref. to NT-5, BATTERY, NOTE, Note.>
24) Fill engine coolant. <Ref. to CO(w/o STI)-14, FILLING OF ENGINE COOLANT, REPLACEMENT, En-
gine Coolant.>
25) Check the engine oil level and replenish the engine oil if necessary. <Ref. to LU(w/o STI)-10, INSPEC-
TION, Engine Oil.>
26) Install the collector cover.
EX-03125
EX-03039
15WRX_STI_US_EN.book 28 ペー   
EX(w/o STI)-29
Front Exhaust Pipe
EXHAUST
C: DISASSEMBLY
1) Remove the exhaust pipe cover from the turbocharger stay.
2) Remove nuts which hold the center exhaust pipe (front) to the turbocharger, and remove the center ex-
haust pipe (front) together with the turbocharger stay (A).
EX-02991
EX-02992
(A)
15WRX_STI_US_EN.book 29 ペー   
EX(w/o STI)-30
Front Exhaust Pipe
EXHAUST
3) Remove the exhaust pipe cover from the front exhaust pipe.
4) Remove nuts which secure the front exhaust pipe to the turbocharger, and remove the front exhaust pipe
together with the turbocharger stay (A).
EX-02993
EX-02994
(A)
15WRX_STI_US_EN.book 30 ペー   
EX(w/o STI)-31
Front Exhaust Pipe
EXHAUST
5) Remove the exhaust pipe cover from the front exhaust pipe.
EX-02995
15WRX_STI_US_EN.book 31 ペー   
EX(w/o STI)-32
Front Exhaust Pipe
EXHAUST
D: ASSEMBLY
1) Install the exhaust pipe cover to the front exhaust pipe.
Tightening torque:
T1: 6.4 N·m (0.7 kgf-m, 4.7 ft-lb)
T2: 13 N·m (1.3 kgf-m, 9.6 ft-lb)
2) Install the front exhaust pipe together with the turbocharger stay (A) to the turbocharger.
NOTE:
Use a new gasket and self-locking nut.
Tightening torque:
42.5 N·m (4.3 kgf-m, 31.3 ft-lb)
EX-02996
T1
T1
T1
T1
T2
T2
T1
T1
T1
T1
EX-02994
(A)
15WRX_STI_US_EN.book 32 ペー   
EX(w/o STI)-33
Front Exhaust Pipe
EXHAUST
3) Install the exhaust pipe cover to the front exhaust pipe.
Tightening torque:
6.4 N·m (0.7 kgf-m, 4.7 ft-lb)
4) Install the center exhaust pipe (front) together with the turbocharger stay (A) to the turbocharger.
NOTE:
Use a new gasket and self-locking nut.
Tightening torque:
42.5 N·m (4.3 kgf-m, 31.3 ft-lb)
EX-02993
EX-02992
(A)
15WRX_STI_US_EN.book 33 ペー   
EX(w/o STI)-34
Front Exhaust Pipe
EXHAUST
5) Install the exhaust pipe cover to the turbocharger stay.
Tightening torque:
6.4 N·m (0.7 kgf-m, 4.7 ft-lb)
E: INSPECTION
1) Check the connections and welded parts for exhaust leaks.
2) Make sure there are no holes or rusting.
EX-02991
15WRX_STI_US_EN.book 34 ペー